Memoirs of the Geological Survey of India; Palaeontologia Indica. Being Figures and Descriptions of the Organic Remains Procured During the Progress of the Geological Survey of India. Series II. III. V. VI. VIII. (A.) Cretaceous Volume 4

Memoirs of the Geological Survey of India; Palaeontologia Indica. Being Figures and Descriptions of the Organic Remains Procured During the Progress of the Geological Survey of India. Series II. III. V. VI. VIII. (A.) Cretaceous Volume 4

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1872 edition. Excerpt: ...abruptly, sloping; the lower surface is flat, slightly depressed round the aperture, which is central, subpentagonal, surrounded by five large, subpiramidal, and five intermediate, smaller, elongately diamond-shaped tubercles, or rather flattened 'ridges. The oral ambulacra are well developed, each composed of three or four irregularly placed-small pores, one series extending along the outer margins of the smaller tubercles, which the ambulacra surmount; the two branches are connected by a few larger scattered pores. The whole upper and the longitudinal median region of the lower side are finely granular, the rest of the lower surface coarsely tubercular, the large mam millated tubercles more or less extending on the oral prominences, while towards the margins they gradually decrease in size and pass at the edges into granules. The apex is central or very nearly so, composed of four genital plates, of which the two posterior and the left anterior are largely perforated, while the right anterior or the madreporiform is largest, porose, occupying the whole centre of the apex, but it has not a larger opening. '.lhe petala are very unequal, none of them extending even within close proximity of the periphery. The anterior ambulacrum is the longest, the antero-laterals are slightly shorter, and one of the postero-laterals scarcely exceeds three-fifths of the length of the anterior impair one; the anterolaterals diverge under an angle of about 145, and the posteriors only under an angle of 415. All the petals are very much narrowed towards their ends, and the ambulacral space between the poriferous zones is generally slightly higher than the adjoining interambulacral. The anus is situated at the upper, very much narrowed, bottle-shaped...show more

Product details

  • Paperback | 94 pages
  • 189 x 246 x 5mm | 181g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 123692097X
  • 9781236920973